SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cb4835d8adaf336f522f711a16d868b34393c4f60f421a0efb45aea5505047a0' 
  AND token = 'h2ByXJ12ipkvzzXmMCeZzv2b4sYgAUsJkM/Y9WZ9INI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}